Three-dimensional printing, also known as additive manufacturing, is a process of making a three-dimensional solid object from a digital model of virtually any shape. Many three-dimensional printing technologies use an additive process in which an additive manufacturing device forms successive layers of the part on top of previously deposited layers. Some of these technologies use extrusion printing in which an extruder emits a melted build material, such as heated and softened ABS plastic, in a predetermined pattern. The printer typically operates the extruder to form successive layers of the build material that form a three-dimensional printed object with a variety of shapes and structures. While many printers employ an extruder that includes a single nozzle to emit the melted material, some extruders include multiple nozzles.
Multi-nozzle extruders include arrays of two or more nozzles that emit at least one type of extrusion material from a single extruder. In some multi-nozzle extruder embodiments, each nozzle is connected to a valve that opens and closes to activate and deactivate individual nozzles dynamically during an additive manufacturing process. Multi-nozzle extruders improve the speed of additive manufacturing processes compared to older single-nozzle extrusion devices while also enabling the three-dimensional object printer to form the extrusion material with high-resolution structures. However, multi-nozzle extruders also require more precise alignment than single-nozzle extruders to maintain the proper alignment between multiple nozzles that are arranged in a two-dimensional array in the extruder. Properly aligned nozzles emit the extrusion material in predetermined locations to ensure that the patterns of extruded materials from multiple nozzles do not overlap each other or have unexpectedly large gaps between different sets of extrusion material from the different nozzles in the extruder. However, misalignment of the nozzles in a multi-nozzle extruder may occur due to an undesirable rotation or “roll” in the extruder that often occurs during operation of three-dimensional object printer. Consequently, improvements to three-dimensional object printers that enable the detection and correction of extruder roll would be beneficial.